Multiplex bacterial PCR in the bronchoalveolar lavage fluid of non-intubated patients with suspected pulmonary infection: a quasi-experimental study.

Background: Early pathogen identification in pulmonary infection is crucial to guide antibacterial therapy and decrease length of hospital stay. We hypothesise that compared to conventional diagnostic methods, a multiplex bacterial polymerase chain reaction assay has a higher diagnostic yield in bronchoalveolar lavage (BAL) fluid and improved clinical outcomes in patients with suspicion of pulmonary infection. Methods: A prospective, monocentric, quasi-experimental, observational study was carried out. Unselected patients with suspected pulmonary infection who underwent bronchoscopy with BAL were included in the study over a period of 1 year. In addition to conventional diagnostic methods, a multiplex PCR bacterial assay was performed in BAL on a 2 week on: 1 week off pre-determined schedule. No therapeutic recommendations were provided to the treating physician. Results: 605 cases were included, 54% of whom were immunosuppressed. Conventional diagnostic methods detected 56% of the bacteria evidenced by PCR. PCR failed to detect bacteria in 4% of the cases with a positive conventional diagnostic result. After bronchoscopy, 42% of the patients received antibacterial therapy for pulmonary infection for a median of 12 antibiotic days. There was no statistically significant difference in length of hospital stay (median 8 versus 8; p=0.839), antibiotic exposure (median 11 versus 14; p=0.362) or number of antibiotics prescribed (median 2 versus 2; p=0.595) between the two groups. Conclusions: A multiplex bacterial PCR detected more bacteria in BAL fluid than conventional diagnostic methods. However, without a specific antibiotic stewardship approach and a clear understanding of the clinical implications of a positive or negative PCR result, the PCR results did not influence clinical outcomes.

High-quality lung fixation by controlled closed loop perfusion for stereological analysis in a large animal model.

BACKGROUND: Stereology is an essential method for quantitative analysis of lung structure. Adequate fixation is a prerequisite for stereological analysis to avoid bias in pulmonary tissue, dimensions and structural details. We present a technique for in situ fixation of large animal lungs for stereological analysis, based on closed loop perfusion fixation. MATERIALS AND METHODS: Twenty anesthetized ventilated pigs (30 ± 3 kg) underwent cannulation of the pulmonary artery and ligation of the right hilus. Following circulatory arrest a continuous positive pressure of 12 mbar was applied to the airways and lung perfusion started with the fixative solution (1.5% paraformaldehyde; 1.5% glutaraldehyde in 0.15 M HEPES). In five animals, a single-pass perfusion technique was performed, in 15 subsequent animals, the closed-loop technique was applied. Afterwards, lungs were removed, externally postfixed in the recycled fixative solution, and stored at 4 °C. Fifteen lung specimens underwent stereological analysis with volume estimation and subsequent systematic uniform random sampling for light and electron microscopic analysis. RESULTS: Singlepass perfusion did not result in satisfactory fixation. Left lung closed loop perfusion rate was 0.5-0.7 L/min with total median [min-max] perfusion time of 15 min (11-19). Perfusion pressure was 15 mm Hg (9-33). Subsequent lung analysis revealed well-preserved cell and tissue ultrastructure. CONCLUSION: The closed loop perfusion technique represents a valuable and reproducible fixation method in large animal models. Pressure controlled fixation perfusion results in high-quality preservation of in situ parenchymal architecture of lungs with or without injury, which is ideally suited for quantitative assessment of lung structure by stereology.

Left-sided mouse intubation: description and evaluation.

A method of left main bronchus intubation was developed based on a wire guide-based microscopic endotrachael mouse intubation technique. The authors used a 22 G x 1 inch catheter elongated by a 38-mm silicone tube, and a wire guide with a tag to assign the length of the wire completely covered by the silicon tube. The isoflurane-anesthetized mouse was hung perpendicularly with its incisors on a thread and transorally intubated under strict vision with the wire guide tip advanced 3 mm out of the catheter. Then the catheter was advanced about 6 to 8 mm into the trachea. Afterwards the wire guide was redrawn to the level of the catheter tip (blue tag on the wire guide appeared at the upper end of catheter) to prevent injury. Then the neck was pushed into a right lateral flexion with one finger against a foam block fixed on the vertical plate, causing a straight distance between mouth and left main bronchus. This positioning allows to gently advance the catheter into the left main bronchus by another about 20 mm, using the wire guide with its tip just within the tube, to achieve there a wedge position with gentle pressure.The technique had a success rate of more than 80% in 81 mice weighing 23 to 48 g. It may be of interest for unilateral lung intervention, e.g., with injurious substances or with drugs.

Outcome of a four-hour smoking cessation counselling workshop for medical students.

BACKGROUND: Lack of smoking cessation education in undergraduate medical training hinders healthcare professionals in providing adequate tobacco cessation counselling. We developed a comprehensive 4-h smoking cessation counselling course for medical students that is easy to incorporate in a medical school curriculum, and assessed its short-term outcome for knowledge, skills, and attitudes. METHODS: Eighty-eight medical students (53f, 35 m) were educated by a doctoral student in five identical 4-h courses. A 45-min theoretical introduction was followed by patient-physician role-playing by student pairs. Knowledge, skills, and attitude were assessed before and 4 weeks after the course by questionnaires, and by blinded analysis of pre- and post-course videos of a five-minute standardized patient situation. RESULTS: Knowledge: Before the course 10.6 (mean, SD: 2.7) questions out of 29 were answered correctly, and increased to 19.2 (3.6) after the course (p < 0.0005). Major features of the students' counselling skills improved. Significant and highly relevant attitude changes reflected increased motivation to counselling smokers. CONCLUSION: Implementing a four-hour smoking intervention workshop into a medical curriculum was highly effective in improving students' knowledge, skills and attitudes towards smoking counselling, as well as providing them with additional clinical competencies.